Not so dumb. But a simple Google search for "electrical downtilt" results in:
http://www.eng-tips.com/viewthread.cfm?qid=145707&page=11 The first result. Gives a simple, clear answer as far as I read it. Chuck On Mar 31, 2010, at 8:26 AM, Mark McElvy wrote: > Ok, dumb question time. How does electrical downtilt work on an omni? > > -----Original Message----- > From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] On > Behalf Of Josh Luthman > Sent: Tuesday, March 30, 2010 9:50 PM > To: sarn...@info-ed.com; WISPA General List > Subject: Re: [WISPA] Ubiquiti Sector Tilt angle > > Electrical down tilt helps for that kind of installation. > > On 3/30/10, Scottie Arnett <sarn...@info-ed.com> wrote: >> As a rule of thumb, as the dB gets higher(or smaller in negative > speak) in >> an antenna, the beam width of the opposing polarity of the antenna > gets >> smaller, and thus harder to work with. >> >> As an example, I have used 15dB Omni's in 2.4Ghz(I'll leave the brand >> unannounced). I first put them about 60 feet in the air and found that > I >> could not get a good usable signal unless I was about 2 miles or so > from the >> tower. I dropped them to 20 - 25 feet and picked up clients within .25 > miles >> out to a couple of miles. The horizontal beam width on the Omni was so >> small, I was way overshooting my intended target. >> >> Lesson learned was to always look at both vert and horiz beam width, > and >> lesson learned on the 15dB Omni is to only use in trailer parks, very > small >> subdivisions, and RV parks... and ... to not mount it above 30 feet > high. >> >> Scottie >> >> ---------- Original Message ---------------------------------- >> From: "Robert West" <robert.w...@just-micro.com> >> Reply-To: WISPA General List <wireless@wispa.org> >> Date: Mon, 29 Mar 2010 18:41:21 -0400 >> >>> Well, I've been setting up a service contract with my friends on > planet >>> Wispalon so I need to find the proper tilt angle to beam the signal > into >>> space. :) >>> >>> Yeah, I've been mindful to stay off the horizon, seems wasteful in a > big >>> way. I'm not a trig scholar so I use basic tilt angle calculators > which >>> have never failed me but these things have me upside down. Tower > height, >>> distance desired and all are good to have but I was really interested > in >>> others experiences with them and how they have been able to get their >>> angles. Again, the smaller, lower gain sectors have been right on the >>> money >>> but I wasn't aware (ignorant) that these high gain units would give me > a >>> smaller slice to work with. On the advice of another member I have > been >>> trying one AP with 4 120 degree 19dbi sectors used as 90's. Signal is >>> great >>> where we can see it, just needed a good fix for not having to do the 2 > man >>> show all over the county. (With everyone in a pickup truck stopping > to ask >>> why we're by the road with an antenna) >>> >>> Bob- >>> >>> >>> -----Original Message----- >>> From: wireless-boun...@wispa.org [mailto:wireless-boun...@wispa.org] > On >>> Behalf Of Lawrence E. Bakst >>> Sent: Monday, March 29, 2010 5:50 PM >>> To: WISPA General List >>> Subject: Re: [WISPA] Ubiquiti Sector Tilt angle >>> >>> Technically speaking you're wrong. The highest gain area of a sector >>> antenna >>> is the center point between the horizontal and vertical spreads. If > you >>> don't downtilt you are sending the strongest part of the signal > parallel to >>> the horizon. Why would you ever want to do that? The whole reason you >>> downtilt is to get the strongest signal pointed to the area you want. >>> >>> Figuring this out takes some basic trig calcs using the tangent > function. >>> >>> No one has asked the most important questions you need to know when >>> calculating downtilt: >>> >>> 1. How high up is the sector antenna? >>> >>> 2. How far out or in what range near to far do you want the sweet > spot? >>> >>> 3. How close in to the tower do you need service? >>> >>> #2 and #3 can conflict with each other and you may have to make a > tradeoff. >>> >>> leb >>> >>> At 2:22 PM -0400 3/29/10, Faisal Imtiaz wrote: >>>> ..... Technically speaking.. if you are not concerned about dealing > with >>>> 'near' customers.... less than 1 or 2 miles... then you can pretty > much >>>> leave the sectors at '0' tilt.. and you have coverage to the > horizon.... >>>> >>>> The built-in electrical down-tilt typically throws folks off...... > only >>>> becomes a factor if you are needing to down tilt for near customers.. >>>> >>>> Faisal. >>>> >>>> On 3/29/2010 1:36 PM, Robert West wrote: >>>>> I'm having a heck of a time with the large UBNT sectors getting the > tilt >>>>> angle to jive. With the smaller sectors, they behave perfectly and > go >>> right >>>>> where the calculations say they will however, with the larger ones, >>> nothing >>>>> I do other than have someone 10 miles out with a CPE check levels > while >>>>> I >>>>> tilt up and down seems to be good. I REALLY don't want to have to > do >>> that >>>>> with all of them... >>>>> >>>>> >>>>> >>>>> Anyone having any success or insight with the proper tilt of these >>> things? >>>>> Using the 120 degree 5GHz flavors. >>>>> >>>>> >>>>> >>>>> Thanks! >>>>> >>>>> >>>>> >>>>> Robert West >>>>> >>>>> Just Micro Digital Services Inc. >>>>> >>>>> 740-335-7020 >>>>> >>>>> >>>>> >>>>> Logo5 >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>> ---------------------------------------------------------------------- > ------ >>> ---- >>>>> WISPA Wants You! Join today! >>>>> http://signup.wispa.org/ >>>>> >>> ---------------------------------------------------------------------- > ------ >>> ---- >>>>> >>>>> WISPA Wireless List: wireless@wispa.org >>>>> >>>>> Subscribe/Unsubscribe: >>>>> http://lists.wispa.org/mailman/listinfo/wireless >>>>> >>>>> Archives: http://lists.wispa.org/pipermail/wireless/ >>>> >>>> >>>> --------------------------------------------------------------------- > ------ >>> ----- >>>> WISPA Wants You! Join today! >>>> http://signup.wispa.org/ >>>> --------------------------------------------------------------------- > ------ >>> ----- >>>> >>>> WISPA Wireless List: wireless@wispa.org >>>> >>>> Subscribe/Unsubscribe: >>>> http://lists.wispa.org/mailman/listinfo/wireless >>>> >>>> Archives: http://lists.wispa.org/pipermail/wireless/ >>> >>> >>> -- >>> l...@iridescent.org >>> >>> >>> >>> ---------------------------------------------------------------------- > ------ >>> ---- >>> WISPA Wants You! 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Join today! > http://signup.wispa.org/ > ------------------------------------------------------------------------ > -------- > > WISPA Wireless List: wireless@wispa.org > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.791 / Virus Database: 271.1.1/2752 - Release Date: 03/30/10 > 01:32:00 > > > -------------------------------------------------------------------------------- > WISPA Wants You! Join today! > http://signup.wispa.org/ > -------------------------------------------------------------------------------- > > WISPA Wireless List: wireless@wispa.org > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ -------------- Chuck Bartosch Clarity Connect, Inc. 200 Pleasant Grove Road Ithaca, NY 14850 (607) 257-8268 "When the stars threw down their spears, and water'd heaven with their tears, Did He smile, His work to see? Did He who made the Lamb make thee?" >From William Blake's Tiger!, Tiger! -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
